Before we begin with our list of 40 piranha facts, we need to tell you something – they aren’t human killers. Hollywood has, from time to time, sent wrong information about many things around us and piranhas are just one of the victims. 

The not so darling reputation of the piranhas, is a result of Hollywood’s misrepresentation of the true self of this omnivore fish. Remember that the notion – ‘piranhas are people killers’ – is nothing but a legend manufactured by a handful of people. So, let us waste time no further and begin with our list. You ready?


Piranha Facts 1-5

1. One of the primary reasons why piranhas have acquired their epic fearsome reputation is Hollywood, but you know what? You can partially blame Theodore Roosevelt for this.

2. In 1913, Roosevelt went to South America. There he saw quite a number of exotic species of animals and birds. He even saw piranhas. He came back and wrote a book – Through the Brazilian Wilderness. The book turned out to be a bestseller. It is this book where he described piranhas and gave them a seriously bad reputation. Want to read his description? Here it is:

Piranha Description by Roosevelt:

They are the most ferocious fish in the world. Even the most formidable fish, the sharks or the barracudas, usually attack things smaller than themselves. But the piranhas habitually attack things much larger than themselves. They will snap a finger off a hand incautiously trailed in the water; they mutilate swimmers—in every river town in Paraguay there are men who have been thus mutilated; they will rend and devour alive any wounded man or beast; for blood in the water excites them to madness. They will tear wounded wildfowl to pieces; and bite off the tails of big fish as they grow exhausted when fighting after being hooked.

3. In his book Roosevelt actually recounted how he saw the piranhas devoured a cow. However, it so happened that the locals there captured several piranhas from the river and placed them in a tank and left them unfed.

When Roosevelt went there, in order to put up a show the locals dropped a dead cow into the river and then all the hungry piranhas were released in the river. No wonder, the carnivore piranhas feasted on the carcass. – Source.

4. Piranhas are pretty common in South America. From Venezuela’s Orinoco River Basin to Argentina’s Parana River, there are 30 different species of piranhas that live in South America.

5. Scientists have dug up fossil evidence of piranhas in South America and dated them as old as 25 million years. However, the fossils that have been recovered widely deviate from the genera that are present today.

The present genera are estimated to be just 1.8 million years in the survival timeline – still older than humans (as per modern accepted timeline of human existence).

Piranha Facts 6-10

6. A study was conducted back in 2007. In the study it was concluded that the modern genera of South American piranhas diverged from their ancestors some 9 million years ago. Some 5 million years ago, the Atlantic Ocean decided to rise and expand into the flood plains of rivers flowing through South America (including the Amazon).

7. As the Atlantic rose, salt water made it to the inroads of the river plains, making it difficult for freshwater fish to thrive, forcing them to escape to higher altitudes.

Well, this led the scientists to conduct genetic analysis of piranhas and they found that those genera that live above 100 meters in Amazon have been calling the place their home for just 3 million years.

8. South America isn’t the only place where you can find piranhas. They can be found roan in waterways of China, Great Britain and even Texas etc. There is a teeny tiny problem here. Piranhas aren’t indigenous to aforementioned places. They are a result of aquarium-to-natural-water-bodies transfer.

9. What does that mean? It simply means that there are people in this world who have this pet-attraction towards piranhas and adorn their aquariums with these fish.

Eventually, the fish become large enough to stay confined in the glass room filled with water. That’s when the owners dump them in local water bodies. One problem! Piranhas are invasive by nature and the pet lovers simply don’t get that! All they know is that keeping a piranha is legal.

10. Did you know that there used to be a language known as Tupi? The classical or old Tupi language is an extinct language that was used in Brazil. Piranha in classical Tupi actually means tooth fish.

Piranha Facts 11-15

11. The question is, ‘why did we turn our focus on the name?’ That’s because toothfish have very interesting teeth that are responsible for relentless biting and also each tooth of the piranha is razor-sharp.

12. Interlocking single rows of teeth lined up along the jaw among adult piranhas look like blades and are perfect for the meaty diet they usually thrive on.

13. True piranhas can be easily identified with their tricuspid teeth. The crown or the middle cuspid is way more pronounced than the remaining two. The crown is nearly 4 millimeters tall.

14. The enamel found on teeth of piranhas is similar to enamel that is found on teeth of sharks. One interesting thing about piranhas is that they keep losing their teeth all throughout their life.

However, the teeth also get replaced in quarters. It is not unlikely to see a piranha which has half of its teeth missing on the lower jaw.

15. Try and ignore fiction movies on piranhas. They are not at all true. However, these fish do have some extraordinary bite force. Just how much force? This force was calculated in a scientific study and later published in the journal Scientific Reports.

Piranha Facts 16-20

16. In the aforementioned study that was conducted back in 2012, the species known as Serrasalmus rhombeus was studied. The species in question is either red-eyed or black-eyed and is known to be the largest of all piranha species of modern times.

It was found that they can bite with a force which is thrice their own body weight. The maximum force they can exert is 72 pounds. Doesn’t sound much? Well, the piranhas aren’t big either!

17. However, if you are not really satisfied with modern species, travel back 10 million years and meet Megapiranha paranensis. That’s an extinct ancestor of modern day piranhas and members of the species actually grew up to 22 pounds or 10 kilos in weight. That’s pretty big.

Fellows of that species exerted a force of 1,068 pounds, which is about 50 times their own body weight! Guess what? That force came from the tip of the jaws!

18. Just to put in perspective, Tyrannosaurs Rex had 3 times the bite force of Megapiranha paranensis. Also, T. Rex was far bigger than the ancient piranha species in question. So, how did the scientists know this? They managed to get a fossil sample of jaws of Megapiranha and conducted a bite force test.

19. If you are not already dead or if you are not dying, you are actually safe if you are facing piranhas. Piranhas won’t eat you if you are healthy and alive and happily swimming among them. All that you see in movies is myth.

20. According to experts, it will take around 300 to 500 piranhas to strip off all flesh from a human weighing 180 pounds in just 5 minutes. While there are examples of dead bodies found with piranha bites, the only problem was that the people were drowned and dead before becoming piranha meal – but that too just a few nibbles.

Piranha Facts 21-25

21. Believe it or not, piranhas do feast on mammals. Not the big ones though. They do eat up small mammals. You may often come across video footage of piranhas killing capybaras. However, you need to know that just as in case with humans, piranhas will feast on mammals if they are already dead or are dying.

22. Piranhas are usually known for eating other fish, insects, carrion, crustaceans, etc. They even feed on plant parts and seeds, making them omnivores.

There are some piranhas that are purely vegan, and they don’t even think of meat. One such species is Tometes camunani found in Para, Brazil’s Amazonian rapids of Trombetas basin. This species lives on riverweed.

23. There is another species known as Catoprion mento or simply known as wimple piranhas that are known for feasting on fish scales. Why so? That’s because the scales have a layer of protein mucus, which is very nutritious.

24. Here is one of the most surprising piranha facts – they can become cannibals depending on the scarcity of the food resources. They might just bite off a piece of flesh from the bodies of their brothers and sisters, either alive or dead if the food sources become scarce.

25. Scientists wondered exactly how the piranhas attacked their prey, especially other fish. In order to find out a laboratory test was conducted in 1972 where a goldfish was put among the carnivores.

It turned out the red-bellied piranhas attacked the tail and eyes of the goldfish. Eventually, the scientists came to a conclusion that by taking the tail-and-eye attack strategy, piranhas effectively immobilize their prey and then feast!

Piranha Facts 26-30

26. For some odd reason, red-bellied piranhas have been a subject of greater number of studies than other species. One such research led the scientists to a conclusion that the red-bellied piranhas are known for making bark-like sounds. Belgian scientists investigated further and found that they actually make 3 different types of sounds.

27. The first type of sound is the bark-like sound. These are actually quick calls that are meant for warning other fish that messing with them will not give good end results.

28. The second type of sounds are thud sounds or low grunts which are made when they piranhas fight or circle other fish. These sounds are more like direct threats.

29. The final sound comes from gnashing of teeth when the piranhas actually start chasing other fish. This is like, ‘I will kill you now’ – super angry, you know!

30. The first two types of vocalizations are outputs of an organ that contains gas. This organ, known as the swim bladder, is responsible for keeping the piranhas afloat. The muscles of the organ are contracted and relaxed for emitting sounds of different frequencies.

Piranha Facts 31-35

31. Piranhas aren’t really that brave you know. They travel in packs which gives an impression that they are displaying their strength. The opposite is true. They are actually scared and moving in packs gives them safety. This behavior is predominant in red-bellied piranhas.

32. Scientists have found that in a piranha shoal older and larger fish are present towards the middle while the smaller and younger ones form the outer edges. This move is a classic safety maneuver.

33. The reason why they actually swim in groups is that they aren’t apex predators in water. They actually are prey of others like river dolphins, birds and caimans and even other pescatarian fish that are larger in size. Moving in shoals gives piranhas a safety net that also displays that they can take on larger predators because of their sheer numbers.

34. Again the red-bellied piranhas became a subject of study in captivity. It was found that when they were exposed to stimulated predatory threats, they had a more calm response and they breathed easily when they were in shoals.

35. Large shoal formations of piranhas in shallow water is pretty common. This is because shallow waters make them more vulnerable.

Piranha Facts 36-40

36. Piranhas, especially the red-bellied and the black piranhas, can get aggressive. However, they will not really do anything unless they are themselves threatened or humans manage to threaten their eggs. They will simply leave humans unharmed unless they are really threatened or they are really hungry because of scarcity of food.

37. When it comes to biting humans, the fishermen are the ones that become most victims. This happens when they try to get rid of piranhas from fishing nets or hooks. In such situations, piranhas tend to bite just once and that too, they usually target feet and toes.

38. Piranhas have this uncanny attraction towards blood, water splashing and noise. They can sniff a single blood drop in 200 liters of water. So if you are bleeding, it is better to stay away from piranha-infested waters.

39. When it comes to sound or noise, what really happens is that they are accustomed to slashing sound created by fruits or seeds that fall in water from trees. They come hunting for those dropped manna for their survival. So, sitting on a river bank and splashing the piranha-infested water is not a good idea either.

40. Of course, we have this pretty bad image of piranhas but did you know that even humans eat piranhas? For instance, in Brazil there is a region known as Pantanal. People of that region are really fond of piranha soup. There are many other places where piranhas grilled on banana leaves and served with lime and tomatoes is a delicacy!

That completes our list of piranha facts. In case you want us to add more to this list, drop a message!

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